Table 4.

Distribution of cases of cancer of the oral cavity/pharynx and controls, and corresponding ORs and 95% CIs, for drinking >4 cups per day of caffeinated coffee versus nondrinkers in strata of selected covariates

Cancer of the oral cavity and pharynx
Controls (n = 830)Cases (n = 525)OR (95% CI)P for heterogeneity*
Age (y)
    <553761840.60 (0.41–0.88)0.06
    ≥554543410.55 (0.40–0.75)0.02
Sex
    Men6454120.59 (0.42–0.81)<0.01
    Women1851130.46 (0.27–0.78)<0.01
Geographic region
    Europe4121320.63 (0.43–0.92)0.07
    America4183930.60 (0.45–0.80)0.11
Education
    <High school graduate3171390.55 (0.33–0.93)<0.01
    ≥High school graduate5083830.65 (0.45–0.93)<0.01
Tobacco consumption§
    Never tobacco users299690.72 (0.31–1.64)<0.01
    Light tobacco users3221640.53 (0.25–1.13)0.03
    Heavy tobacco users2052900.51 (0.35–0.76)<0.01
Alcohol consumption
    Never or light drinkers5662270.59 (0.42–0.85)<0.01
    Heavy drinkers2432860.61 (0.42–0.85)<0.01
Vegetable intake
    <Median3883070.59 (0.37–0.92)<0.01
    ≥Median4422180.60 (0.39–0.92)<0.01
Fruit intake
    <Median4293540.52 (0.36–0.74)<0.01
    ≥Median4011670.65 (0.41–1.02)<0.01
Type of controls
    Hospital based4181410.65 (0.38–1.11)<0.01
    Population based4123840.58 (0.44–0.78)0.20

NOTE: Random-effects estimates were used when heterogeneity was detected, and fixed-effects estimates otherwise. Adjusted for age, sex, race/ethnicity, education, study, cigarette smoking (pack-years), duration of cigar smoking, duration of pipe smoking, alcohol intake, weight, and vegetable and fruit intake (as appropriate). Reference category was non–coffee drinkers in each stratum.

  • *Between studies.

  • Europe included two studies from Italy (32, 34), one from France (33), and one from Switzerland (35). America included four studies from the United States (1, 36-38) and one from Puerto Rico (39).

  • The sum does not add up to the total because of some missing values.

  • §Light tobacco users were smokers of ≤20 pack-years equivalent (combination of pack-years of cigarettes and equivalent amount of cigars or pipe). Heavy tobacco users were smokers of >20 pack-years equivalent.

  • Never/light drinkers were drinkers of <3 drinks per day of alcoholic beverages and heavy drinkers those consuming ≥3 drinks per day.